When MTS did this, it was a HUGE inconvience,
"On Sunday August 29th through to Sunday September 12th, we will begin blocking access to the ports commonly used to send spam and viruses on MTS High Speed Internet and Dial-up Internet services." Year 2004, just so you have your info correct, I remember haveing this 'issue' dealing with some of the customer calls I took as a tech.
MTS only allows their SMTP servers to be used from inside the MTS network and you can not use anybody else's SMTP servers....
When I was at home, I had to change my outlook settings (I had all mail forwarded to my cell phone as a text message, instant notification of when a mail arrived), when I got to work, I had to change the SMTP server to the companies ISP's server.
That was by far my biggest complaint. However, had I known about SSH Tunneling a few years ago... I would have used that.
Shaw blocking mail, its way more annoying that they block access to the pop server when using a non-Shaw account. (last time I checked, I don't use Shawmail anymore)
Anybody concerned, my Shaw SOHO plan with Tiers 1, 2, and 3 is $90/month tax included (taken from my last statement), which is VERY close to what residential services are. Call to cancel the residential, then call Business Care, since you're already setup, cabling is done, you have a modem, ask the CSR to wave the $100 install fee... Mine did... And then you also get the 5 IPs instead of just 2.